Enrollment in High-Deductible Health Plans and Incident Diabetes Complications

Key Points Question Is switching to a high-deductible health plan (HDHP), when required to do so by an employer, associated with an increased risk of experiencing microvascular and macrovascular complications of diabetes? Findings In this cohort study of 245 055 US adults with diabetes enrolled in employer-sponsored health plans, required transition to an HDHP was associated with increased odds of experiencing all examined microvascular and macrovascular complications of diabetes. Meaning People with diabetes who are required to switch to HDHPs may be more likely to experience diabetes complications than those who remain in conventional insurance plans, which suggests a need for policy solutions to address health plan–mediated barriers to diabetes management.


eMethods. Study Design
This was a stepped wedge study design, where each patient who switched to a high-deductible health plan (HDHP) served as their own control, while those who never switched served as contemporaneous controls.Accordingly, we used analytic methods appropriate for a stepped wedge design with repeated measures on individuals.[3] We chose to use calendar year as the unit of observation for several reasons.First, lower event rates would make modeling shorter time periods challenging.Second, we anticipated that the effect of switching health plans would not be immediately measurable; rather, that if higher deductibles led to reduced or deferred care this would lead to diabetes complications and their related visits over longer periods of time, such as a year.Third, longer observation periods (e.g., pre and post design pooling all unexposed and exposed time) would not easily allow us to incorporate multiple time periods per individual, nor would we be able to align observations across exposed and unexposed groups.Using calendar year as our unit of observation allows us to treat each year as the 'step' of a stepped wedge design and compare exposed and unexposed individuals directly.

eTable 1 . 2 . 3 . 5 . 6 . 7 . 8 .
Minimum Deductible to Qualify for a Health Savings Account (HSA) Limit, as Defined by the Internal Revenue Service (IRS) eTable List of Included Glucose-Lowering Medications eTable International Classification of Disease (ICD)-9 and ICD-10 Codes Used for Baseline Covariates eTable 4. International Classification of Disease (ICD)-9 and ICD-10 Codes Used for Study Outcomes eFigure.Flow Chart eTable Association Between Required Switch to HDHP and Incident Diabetes Complications: Sensitivity Analysis Assessing for Potential Interaction With Patient Race/Ethnicity eTable Association Between Required Switch to HDHP and Incident Diabetes Complications: Sensitivity Analysis Assessing for Potential Interaction With Patient's Annual Household Income eTable Association Between Required Switch to HDHP and Incident Diabetes Complications: Sensitivity Analysis With Medication Adjustment eTable Impact of HDHP Enrollment Duration on Incidence of Diabetes Complications: Sensitivity Analysis With Medication Adjustment eReferences This supplementary material has been provided by the authors to give readers additional information about their work.eMethods.Study Design.

Association between required switch to HDHP and incident diabetes complications: sensitivity analysis assessing for potential interaction with patient race/ethnicity.
Multivariable regression examined the association between switching to a HDHP and the incidence of diabetes complications, with an added interaction term between HDHP status and patient race/ethnicity (non-White vs. White).Models are adjusted for patient demographics (age, sex, race/ethnicity, U.S. region, and annual household income), index year, baseline comorbidities and, the Diabetes Complications Severity Index (DCSI) complications count.Analyses of blindness, retinopathy, EKSD, and lower extremity amputation outcomes excluded patients with these conditions at baseline and excluded the corresponding diagnoses from baseline adjusters.* To account for multiple testing for 8 outcomes we used a Sidak adjusted significance level; two-sided p-values <0.006 were considered statistically significant.

Association between required switch to HDHP and incident diabetes complications: sensitivity analysis assessing for potential interaction with patient's annual household income.
Multivariable regression examined the association between switching to a HDHP and the incidence of diabetes complications, with an added interaction term between HDHP status and patient's annual household income (≥$40,000 [includes missing/unknown] vs. <$40,000).Models are adjusted for patient demographics (age, sex, race/ethnicity, U.S. region, and annual household income), index year, baseline comorbidities, and the Diabetes Complications Severity Index (DCSI) complications count.Analyses of blindness, retinopathy, EKSD, and lower extremity amputation outcomes excluded patients with these conditions at baseline and excluded the corresponding diagnoses from baseline adjusters.* To account for multiple testing for 8 outcomes we used a Sidak adjusted significance level; two-sided p-values <0.006 were considered statistically significant.

Association between required switch to HDHP and incident diabetes complications: sensitivity analysis with medication adjustment.
Models are adjusted for patient demographics (age, sex, race/ethnicity, U.S. region, and annual household income), index year, baseline comorbidities, the Diabetes Complications Severity Index (DCSI) complications count, and baseline classes of medications.Analyses of blindness, retinopathy, EKSD, and lower extremity amputation outcomes excluded patients with these conditions at baseline and excluded the corresponding diagnoses from baseline adjusters.* To account for multiple testing for 8 outcomes we used a Sidak adjusted significance level; twosided p-values <0.006 were considered statistically significant.

Impact of HDHP enrollment duration on incidence of diabetes complications: sensitivity analysis with medication adjustment.
Odds ratios (OR) present the incremental change in the risk of each diabetes complication per additional year of enrollment in an HDHP.Models are adjusted for patient demographics (age, sex, race/ethnicity, U.S. region, and annual household income), index year, baseline comorbidities, the Diabetes Complications Severity Index (DCSI) complications count, and baseline classes of medications.Analyses of blindness, retinopathy, EKSD, and lower extremity amputation outcomes excluded patients with these conditions at baseline and excluded the corresponding diagnoses from baseline adjusters.* To account for multiple testing for 8 outcomes we used a Sidak adjusted significance level; two-sided p-values <0.006 were considered statistically significant.